Merge pull request #18 from awatterott/master

Add getAltitudeCompensation()

Author: nseidle

examples/Example2_SetOptions/Example2_SetOptions.ino

@@ -42,18 +42,25 @@ void setup()
 
   airSensor.setMeasurementInterval(4); //Change number of seconds between measurements: 2 to 1800 (30 minutes)
 
+  //Read altitude compensation value
+  unsigned int altitude = airSensor.getAltitudeCompensation();
+  Serial.print("Current altitude: ");
+  Serial.print(altitude);
+  Serial.println("m");
+
   //My desk is ~1600m above sealevel
-  airSensor.setAltitudeCompensation(1600); //Set altitude of the sensor in m
+  airSensor.setAltitudeCompensation(1600); //Set altitude of the sensor in m, stored in non-volatile memory of SCD30
 
   //Pressure in Boulder, CO is 24.65inHg or 834.74mBar
-  airSensor.setAmbientPressure(835); //Current ambient pressure in mBar: 700 to 1200
+  airSensor.setAmbientPressure(835); //Current ambient pressure in mBar: 700 to 1200, will overwrite altitude compensation
 
+  //Read temperature offset
   float offset = airSensor.getTemperatureOffset();
   Serial.print("Current temp offset: ");
   Serial.print(offset, 2);
   Serial.println("C");
 
-  //airSensor.setTemperatureOffset(5); //Optionally we can set temperature offset to 5°C
+  //airSensor.setTemperatureOffset(5); //Optionally we can set temperature offset to 5°C, stored in non-volatile memory of SCD30
 }
 
 void loop()

src/SparkFun_SCD30_Arduino_Library.cpp

@@ -123,7 +123,7 @@ bool SCD30::setForcedRecalibrationFactor(uint16_t concentration)
 }
 
 //Get the temperature offset. See 1.3.8.
-float SCD30::getTemperatureOffset()
+float SCD30::getTemperatureOffset(void)
 {
   uint16_t response = readRegister(COMMAND_SET_TEMPERATURE_OFFSET);
   return (float)response / 100;
@@ -136,6 +136,12 @@ bool SCD30::setTemperatureOffset(float tempOffset)
   return sendCommand(COMMAND_SET_TEMPERATURE_OFFSET, tickOffset);
 }
 
+//Get the altitude compenstation. See 1.3.9.
+uint16_t SCD30::getAltitudeCompensation(void)
+{
+  return readRegister(COMMAND_SET_ALTITUDE_COMPENSATION);
+}
+
 //Set the altitude compenstation. See 1.3.9.
 bool SCD30::setAltitudeCompensation(uint16_t altitude)
 {

src/SparkFun_SCD30_Arduino_Library.h

@@ -61,6 +61,7 @@ class SCD30
 	float getHumidity(void);
 	float getTemperature(void);
 	float getTemperatureOffset(void);
+	uint16_t getAltitudeCompensation(void);
 
 	bool setMeasurementInterval(uint16_t interval);
 	bool setAmbientPressure(uint16_t pressure_mbar);